I could enamel you could enamel he could enamel we could enamel you could enamel they could enamel
V-ing form
I could be enamelling you could be enamelling he could be enamelling we could be enamelling you could be enamelling they could be enamelling
Perfect
I could have enamelled you could have enamelled he could have enamelled we could have enamelled you could have enamelled they could have enamelled
V-ing perfect
I could have been enamelling you could have been enamelling he could have been enamelling we could have been enamelling you could have been enamelling they could have been enamelling
Negation
Simple form
I couldn't enamel you couldn't enamel he couldn't enamel we couldn't enamel you couldn't enamel they couldn't enamel
V-ing form
I couldn't be enamelling you couldn't be enamelling he couldn't be enamelling we couldn't be enamelling you couldn't be enamelling they couldn't be enamelling
Perfect
I couldn't have enamelled you couldn't have enamelled he couldn't have enamelled we couldn't have enamelled you couldn't have enamelled they couldn't have enamelled
V-ing perfect
I couldn't have been enamelling you couldn't have been enamelling he couldn't have been enamelling we couldn't have been enamelling you couldn't have been enamelling they couldn't have been enamelling
Interrogative form
Simple form
could I enamel? could you enamel? could he enamel? could we enamel? could you enamel? could they enamel?
V-ing form
could I be enamelling? could you be enamelling? could he be enamelling? could we be enamelling? could you be enamelling? could they be enamelling?
Perfect
could I have enamelled? could you have enamelled? could he have enamelled? could we have enamelled? could you have enamelled? could they have enamelled?
V-ing perfect
could I have been enamelling? could you have been enamelling? could he have been enamelling? could we have been enamelling? could you have been enamelling? could they have been enamelling?
Interro-negative form
Simple form
couldn't I enamel? couldn't you enamel? couldn't he enamel? couldn't we enamel? couldn't you enamel? couldn't they enamel?
V-ing form
couldn't I be enamelling? couldn't you be enamelling? couldn't he be enamelling? couldn't we be enamelling? couldn't you be enamelling? couldn't they be enamelling?
Perfect
couldn't I have enamelled? couldn't you have enamelled? couldn't he have enamelled? couldn't we have enamelled? couldn't you have enamelled? couldn't they have enamelled?
V-ing perfect
couldn't I have been enamelling? couldn't you have been enamelling? couldn't he have been enamelling? couldn't we have been enamelling? couldn't you have been enamelling? couldn't they have been enamelling?